Organic light emitting diode (hereinafter referred to as OLED for short) display devices have attracted wide attention by virtue of characteristics such as self-luminescence, high brightness, wide view angle, high contrast, good flexibility and low energy consumption, and are widely applied to mobile phones, computer displays, full-color televisions and the like as a new-generation of display.
An OLED display device usually comprises a substrate, OLED elements and a packaging structure. The OLED element is located on the substrate. The packaging structure and the substrate jointly form a packaging cavity in which the OLED element is packaged. Since the OLED elements are quite sensitive to oxygen and/or vapor, requirements in the packaging effects of OLED display devices are usually very high. At present, in the production of OLED display devices, the packaging effect of the OLED display devices is monitored or detected to screen out OLED display devices having a packaging failure (OLED display devices in which water and/or oxygen permeates into the packaging cavity) and improve the production yield of OLED display devices.